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THE GENERAL ELECTRIC COMPANY’S INCANDESCENT LAMP FACTORY AT HARRISON, N. J 


CAPACITY PER DAY 35,°oo INCANDESCENT LAMPS—ANNUAL PRODUCTION 6,500,000 LAM-PS. 





Entered according to Act of Congress in the Year 1897, by 
General Electric Company, 

in the Office of the Librarian of Congress at Washington. 










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GENERAL ELECTRIC COMPANY 


MAIN OFFICES, SCHENECTADY, N. Y. 
MAIN LAMP SALES OFFICES. HARRISON, N. J. 



SALES OFFICES: 

BOSTON, MASS., 180 Summer Street. 

NEW YORK, N. Y., 44 Broad Street. 

Syracuse, N. Y., Sedgwick, Andrews & Kennedy Big. 
Buffalo. N. Y., 901 D. S. Morgan Building. 
PHILADELPHIA, PA., 509 Arch Street. 

Baltimore, Md., 227 E. German Street. 

Pittsburg, Pa., 502 Tradesmen’s Bank Building. 
ATLANTA, GA., Equitable Building. 

New Orleans, La., 423 Baronne Street. 
CINCINNATI, OHIO, 420 West Fourth Street. 
Columbus, Ohio, 14 North High Street. 

Nashville, Tenn., 308 North Summer Street. 
CHICAGO, ILL., Monadnock Building. 

Detroit, Mich., 1026 Chamber of Commerce Big. 

St. Louis, Mo., Wainwright Building. 

Dallas, Texas, Junction Building. 

Helena, Mont., Electric Building. 

Minneapolis, Minn., Phoenix Building. 

DENVER, COLO., Kittredge Building. 

SAN FRANCISCO, CAL., 15 First Street. 

Portland, Ore., Worcester Building. 

For all business outside the United States and Canada: 
Foreign Dept., Schenectady, N. Y., and 
44 Broad Street, New York. 


For Canada, address Canadian General Electric Co., Ltd., 
Toronto, Ontario. 

’ • V 


t f 




















PREFACE 


IN PRESENTING THIS CATALOGUE WE HAVE 
ENDEAVORED TO FURNISH THE PURCHASER 
A GUIDE TO THE INTELLIGENT SELECTION OF 
THE LAMP BEST SUITED TO HIS PARTICULAR 
R EQUIR EMENT S. THE O PENING SECTION IS . 
THEREFORE. DEVOTED TO THE MANUFAC¬ 
TURE. SELECTION AND PROPER USE OF 
L AMPS. A ND WE BELIEVE IT W ILL REPAY 
A CAREFUL PERUSAL. DESCRI PTI ONS AND 
FULL SIZE ILLUSTRATIONS OF THE VARIOUS 
TYPES OF OUR LAMPS. INCLUDING STAND¬ 
ARD. SPECIAL AND MINIATURE LAMPS. ARE 
GIVEN IN THE FOLLOWING PAGES, AND THE 
APPENDED GENERAL LAMP DATA SHOULD 
PROVE VALUABLE. 

WE INVITE CORRESPONDENCE REGARDING 
SPECIAL LAMPS OF ANY TYPE, WHICH WE 
ARE PREPARED TO MANUFACTURE TO 
ORDER. 

F OR THE CON VE N 1 ENCE OF OUR PATRO NS. 
L ARGE AND VARIED STOCKS OF LAMPS ARE 
CARRI ED AT THE FOLLO W ING POINTS : 

LAMP FACTORY. HARRISON. N. J. 

ATLANTA, GA. BOS TON, MASS. 

CHICAGO. ILL. _ CINCINNATI, OHIO. 

DENVER COLO. SAN FRANCISCO. CAL. 


SEPTEMBER 20, 1897. 







































The Manufacture of Lamps. 

An incandescent lamp is to the casual observer an extremely simple device consisting 
of a carbon filament in a glass bulb. While it is simple in appearance the perfected incandes¬ 
cent lamp is nevertheless very complex in all its features. It is something more than a 
mechanical product, as its construction involves complex chemical, electrical and physical 
problems, making it a very highly organized article of manufacture. In probably no other 
manufacturing enterprise is success so dependent on experience combined with careful 
systematic testing and inspection, for in the manufacture of incandescent lamps, apparently 
insignificant changes in methods produce most important results, and the cause of defects is, 
therefore, difficult to locate and remedy. 

It will no doubt be surprising to many to learn that every incandescent lamp 
manufactured by the General Electric Company requires fifty distinct constructive operations 
and forty separate tests and inspections to complete it for the market. 
To produce an incandescent lamp and sell it at our present low price 
without omitting any detail of manufacture or test, is an achievement 
rendered possible only by our enormous output and many years of 
experience. The Edison lamp represents the most extended experience 
and the largest production and, therefore, stands superior to all others. 
So varied are the standards of candle-power that we have adopted a 
standard of our own which is higher than the standards of candle-power in use by other 
companies. 

That the candle-power of other makes of lamps is below that of the Edison Lamp is a 
fact easily demonstrated. Not only are other companies’ standards lower, but many companies 
deliberately or unknowingly over-rate their lamps—a practice never permitted with Edison Lamps. 

The average eye can make only a very vague approximation to the true candle-power of a 
lamp, and exact results require the use of a photometer by a practical observer. The subject of 
candle-power is, therefore, very important to the customer, who seldom has apparatus to 
determine whether a lamp is of full rated candle-power. Over-rating of the candle-power, of 
course, involves over-rating of the efficiency. A true 16 candle-power lamp taking 50 watts has 
an efficiency of 3.1 watts per candle, but if it is really only a 13 candle-power lamp marked 
16 candle-power, it will require 3.8 watts per candle. 

Such facts emphasize the importance and value of dealing with the oldest and largest 
manufacturing company whose reliability as to standards and ratings is unquestionable. 

While the low prices of the past two years have compelled many lamp manufacturers to 
save expense by abridging processes and neglecting vital points, we have been improving our 
methods and machinery, giving lamps more detailed attention than ever with the result of 
producing a better and more uniform lamp than was formerly sold at double the present price. 


RESULTS OF 
SKILL AND 
EXPERIENCE 


9 











GENERAL ELECTRIC COMPANY 


OUR NEW 

EXHAUSTION 

PROCESS 


Tnis is possible for us by reason of our immense production of over 6,000,000 lamps per year, 
riiis immense production also permits us to adopt improvements, conduct a laboratory and 
p^rfoim experimental and testing work, the expense of which while only a small fraction of a 
cent pei lamp to us, is absolutely prohibitory to the average lamp company producing only a few 
thousand lamps pei year. It is clearly evident that the lamp company able to most extensively 
conduct such work can give_ its customers a uniformity of product and improvement in quality 
unobtainable by other companies. 

Among the many improvements in manufacture, our new exhaustion 
process may be mentioned as one of the most important in its effect on 
the quality of the product. From time to time during recent years 
mechanical vacuum pumps operated without mercury have been brought 
before the public, and while our engineers have fully appreciated the 
advantages of such pumps they have been prevented from adopting 
any of them owing to the size in which these pumps have been invariably made, the object of 
their inventors being to exhaust a very large number of lamps at the same time, which our 
engineers have always considered bad practice. Recently the Company succeeded in obtaining 
a small mechanical vacuum pump whose rate of exhaustion is such that it can be practically 
employed to exhaust only one lamp at a time. Experiments were begun with these pumps about 
a year and a half ago. These early experiments showed that lamps could be exhausted to a 
degree much nearer perfection than by any previous method employed, as on these pumps the 
lamps are exhausted one by one, each lamp being carefully watched from the start until it is 
laid aside thoroughly exhausted. By the employment in combination with these pumps of a 
chemical process exclusively used by us in the United States, the various phenomena of 
exhaustion are clearly marked so as to enable a very definite rule of operation to be 
worked out. 

The natural residual gases of an incandescent lamp may be considered conducting gases, 
since they allow current to pass from one leg of the filament to the other. The residual gases 
are, therefore, not only very injurious to the filament, but their removal has previously involved 
long and tedious processes. The special feature of our new method of exhaustion, usually 
called the “chemical process,” is the thorough removal of all the residual gases from a lamp 
by the introduction of a gas capable of combining with them. Previous to this introduction a 
blue glow fills the bulb when the filament shows bright incandescence. 
When the combination takes place between the residual gases and the 
new gas, the blue glow suddenly disappears and a lamp “sealed off” at 
this point has a vacuum of perfect insulating properties. 

The advantages of the chemical process of exhaustion are: 

First. The combination of the gases in the bulb is a phenomenon 
so marked as to furnish to the operator an absolute proof that the 
proper vacuum has been attained. 

Second. Lamps are exhausted one at a time and the whole attention of the operator is 
concentrated on a single lamp, thus insuring a perfection of vacuum difficult to obtain when 
lamps are exhausted in groups. 

Third. The operator may sit in a comfortable position and is, therefore, not unduly 
wearied and can do as accurate work late in the day as in the morning. 

Fourth. The injurious effects of mercury upon the health of the operator are entirely 
avoided, enabling us to secure uninterrupted service from our operators and therefore the very 
highest skill which is dependent upon continued practice. 


ADVANTAGES 
OF THE 
PROCESS 


10 




GENERAL ELECTRIC COMPANY 


Our processes of manufacture are manifold, careful and exacting, embodying all the 
improvements and every detail that our judgment and extensive experience show are necessary 
to make a finished lamp of the finest appearance and highest quality—considerations always 
foremost with us. The results are as they should be, the Edison Lamp stands to-day absolutely 
unequalled, the Standard Incandescent Lamp of the world. 

We were the first manufacturers of lamps and have always produced more than the 
combined output of all the other factories in America. We have by constant, careful, intelligent 
and thorough work, steadily increased the commercial possibilities of 
the incandescent lamp, building up the market for it and supplying for 
years a clientage of the largest lamp consumers in the world with the 
most perfect incandescent lamp on the market. The Edison Lamp of 
to-day is farther than ever in advance of other makes, and it has 
opportunities to improve at a far more rapid pace than is possible for 
any other lamp. The Edison Lamp with its eminent superiority is, 
therefore, rapidly leaving all competitors. 

Our present annual production of over six million lamps enables us more easily to 
produce a lamp which justifies the following statement made two years ago by the largest 
consumer of lamps in the world: 

“Comparative tests of ‘New Type Edison Lamps’ with those of other makes, both 
European and American, demonstrate that in maintenance of candle-power, efficiency and 
average life, the ‘ New Type Edison Lamp ’ equals and surpasses them all.” 


SUPERIORITY 
OF THE 
EDISON LAMP 






GENERAL ELECTRIC COMPANY 


The Selection of Lamps. 

In purchasing lamps the average customer considers only two points—the first cost of 
the lamp and the time it will last. Two other points are, however, even more important and 
should not be neglected. One is the efficiency of the lamp, or the number of lamps which can 
be supplied per horse-power. Lamps are classified according to voltage, 
CLASSIFICATION candle-power, efficiency and type of cap or base. The term efficiency is 
used to denote the amount of power consumed by the lamp expressed in 
watts per candle, as for example, “3.5 watts efficiency” means that the 
lamp requires 3.5 watts for each candle-power of light given. High 
efficiency lamps that require small power per candle, are more 
susceptible to variations of pressure and have a shorter life than low 
efficiency lamps that consume relatively more power per candle. 

The Ldison lamp is furnished in three different efficiencies: 

3.1 watts per candle or 12-1G candle-power lamps to the mechanical horse-power. 

3.5 watts per candle or 10-16 candle-power lamps to the mechanical horse-power. 

4 watts per candle or 8-16 candle-power lamps to the mechanical horse-power. 

The other important point to be considered is the period of useful life , beyond which it 
is economy to install a new lamp even though the old one be still unbroken. Mere life is not 
the principal feature of a lamp nor the most desirable. The fact that one lamp outlasts another, no 
more indicates superiority than does the length of a plot of ground determine its area. A lamp 
may be made to give any length of life desired and yet consume so much current as to make 
it cost more to burn than a lamp giving half the life but consuming less power. A lamp may 

also have long life and yet give so low an average of candle-power as to make it a very 

undesirable and worthless lamp. 

The features of first importance in an incandescent lamp, are, therefore, efficiency (energy 
consumed for light given) and maintenance of candle-power. The point to be observed in 
purchasing lamps is therefore to select the lamp in which the average candle-power, energy 
consumed and length of life are combined to produce the best and most economical results,— 
that is, to give the greatest amount of light for least cost. 

It is a fact demonstrated by impartial tests of scientific institutions 
and by the practical experience of the largest electric light companies, 
that the New Type Edison Lamp excels all others in the most efficient 
combination of these desirable qualities. 

The following facts determine the conditions to which each type of 
lamp is best adapted. 

Lamps of an efficiency of 3.1 watts per candle, will give satisfaction 
only wheie the regulation of voltage at the station is the best, or, in other words, where the 
voltage at all times is practically constant. Such regulation can be secured only by constant 
and intelligent attention and the use of reliable indicators or volt-meters. 

Lamps of an efficiency of 3.5 watts per candle should be used where the regulation is 
only fair, that is, where the maximum variation does not exceed 4 °J 0 . 

Lamps of an efficiency of 4 watts per candle should be ordered in every case where the 
plant is supposed to be self-regulating, receives little or no attention, and has no reliable 
pressure indicator or volt-meter in constant use. 


AHEAD 
OF ALL 
COMPETITORS 


OF 

LAMPS 


12 





GENERAL ELECTRIC COMPANY 


Where the regulation of voltage is first-class, it is, of course, possible to obtain almost 
unlimited average life from any make of incandescent lamp of low efficiency. Using lamps of 
such prolonged life is, however, a decided mistake and is uneconomical in every way, as is 
shown in the following section and in the Appendix. 

We invite correspondence regarding the particular conditions under which plants are 
operated, and will be pleased to advise as to what efficiency of lamp will best suit the require¬ 
ments. Whatever efficiency of lamp is selected no one thing will so greatly' increase the 
efficiency of the plant as the effort to maintain constant voltage at the lamps. 



18 




GENERAL ELECTRIC COMPANY 


The Proper Use of Lamps. 

A lamp to give satisfaction must not only be properly made, but it must also be properly 
used. A lamp of the highest quality may be so misused as to give only a small fraction of its 
rated light capacity. Proper use, producing a maximum of light at a minimum expense, requires: 

That the lamps be burned at marked voltage. 

That the voltage be kept constant. 

That lamps be replaced whenever they get dim. 

The last requirement is not considered economical by many users who prize lamps that 
have long life and insist on using them as long as they will burn. Let us see by an example if 
extremely long life is desirable. 

As the cost of current varies greatly, we will assume an average cost of one-half cent per 
lamp hour. If a rated 16 candle-power lamp, burned for 1000 hours, be burned an additional 1000 
hours, it takes practically the same current during the last period, but 
gives an average light of only about 8 candles. The cost of current for 
the 2000 hours is 110.00. A new lamp costs 20 to 25 cents, and had three 
lamps, with a life of about 700 hours each, been used during the entire 
period, the average light would have been fully doubled, at an added 
expense of not more than 50 cents or 5% of cost of current. In other 
words, by adding 5% to operating expense (representing the cost of the 
two renewal lamps) the customer would add 100% to the light given. One new lamp gives a light 
equal to two old ones at half the cost of current. If the old lamps gave light enough, the new 
lamps would halve the number of lamps in use and produce the same light with half the current. 

It is important to note that the above example is based on results obtained with the 
highest grade of lamps. With an inferior quality of lamp the argument against extremely long 
life would be still stronger and the necessity of frequent renewals of lamps much greater. 

I hus, from any point of view, it is false economy to select lamps with a sole regard for 
long life. Lamps should be renewed when dim, for in no other way can light be produced 
economically. 

The points to be remembered are as follows: 

Do not run pressure above the voltage of the lamps. Increased pressure means extra 
power, and, although old lamps may thus give more light for awhile, every new lamp that does 
not break from the excessive pressure, will deteriorate very rapidly and give greatly diminished 
light. 

Do not treat incandescent lamps like lamp chimneys and use them until they break. They 
should be renewed whenever they get dim. 

The section on Life and Candle-power in the Appendix of this pamphlet gives a complete 
discussion of this subject. 


THE ECONOMY 
OF FREQUENT 
RENEWALS 


14 





Standard 
50 Volt 
Incandescent 
Lamps 












GENERAL ELECTRIC COMPANY 


8 and 10 Candle=power 50 Volt Lamps. 

For service requiring only a moderate quantity of light, we furnish our 8 and 10 candle- 
power lamps. Owing to the extreme fineness of the filaments, these lamps are more sensitive to 
variation in voltage than standard 1G candle-power lamps of the same efficiency. For this reason 
to secure uniform average life, lamps of low candle-power should be ordered with lower efficiency 
than the standard 16 candle-power lamps to operate under the same conditions. The filaments 
being comparatively short and stiff are best adapted to the loop form. 



DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size as in illustration. Filament—Loop. 

Voltages—45 to 90. 

Efficiency, 8 candle-power lamp—3.1, 3.5 and 4 watts per candle. 

Efficiency, 10 candle-power lamp—3.1, 3.5 and 4 watts per candle. 

The 10 candle-power 4 watt lamp is furnished in the same size bulb as the standard 16 
candle-power 50 volt lamp. 

Fitted with Standard Edison Screw Base or any of the following bases: Westinghouse, 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


17 







GENERAL ELECTRIC COMPANY 


16 Candle=power 50 Volt Lamp. 




UNIFORM 
LIGHT 
AND LIFE 


Low voltage lamps by reason of their heavier filament give much better results than can 
be obtained with high voltage lamps. This superiority, however, tends to a fault, since low 
voltage lamps are frequently retained too long in service. Their life outlasts their usefulness. 
In no efficient lighting service can it possibly pay to allow such lamps to have an average life 
longer than 1000 hours. Frequent renewals, keeping the average life 
down to this figure or below it will be found to give the best results. 
The tendency of modern practice is to change from low pressure to 
100 volts and over. Im¬ 
provements in high volt¬ 
age lamps have brought 
them so near to the 
naturally better quality of low voltage lamps 
that the objections to their use no longer exist. 

The economy in copper on secondaries, and 
most important of all, the better regulation 
possible on 100 volt circuits have induced a 
change to higher voltages on the part of many 
large companies. 

The standard low voltage lamp has an 
efficiency of 3.5 watts per candle, which is 
preferable on account of the difficulties of good 
regulation on low voltage secondaries. We 
nevertheless have a large clientage of customers 
who use with the greatest satisfaction our low 
voltage 3.1 watt lamp. For such stations as give 
special attention to their secondary regulation, 
the saving in power obtained with our 3.1 watt 
lamps will recommend them for service. 

The bulbs are moulded of uniform size. 

We use the loop form of filament because it is 
the best permissible with a filament necessarily 
too short and stiff for the oval form. 


DESCRIPTION. 


Bulb—Moulded, Pear-shaped, Size as in 
illustration. Filament—Loop. 

Voltages—45 to 90. 

Efficiency, 16 candle-power lamp 3.1, 3.5 and 4 watts per candle. 

Efficiency, 20 candle-power lamp—3.1, 3.5 and 4 watts per candle. 

Efficiency, 24 candle-power lamp—3.1, 3.5 and 4 watts per candle. 

fitted with Standard Edison Screw Base or any of the following bases: Westinghouse, 
1 homson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer.^ 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


IS 




GENERAL ELECTRIC COMPANY 


32 Candle=power 50 Volt Lamp. 


We have adopted the loop filament for 
all our low voltage lamps in preference to 
the spiral, which we have tried and discarded. 
The proper size of filament, to give the 
best results in maintained candle-power and 
freedom from blackening requires a length 
too short to wind in a well formed spiral. 
The spiral filament owing to the weight of 
the coil at the end tends to droop more than 
the loop. Altogether our extensive experi¬ 
ence with low voltage lamps shows that the 
loop form of filament makes a better lamp. 

DESCRIPTION. 

Bulb—Moulded, Size as in illustration. 

Filament — Loop. 

Voltages—45 to 90. 

Efficiency—3.1, 3.5 and 4 watts per 

candle. 

F'itted with Standard Edison Screw 
Base or any of the following bases: Westing- 
house, Thomson-Houston, United States, 
Brush-Swan, Elawkeye, Mather, Perkins or 
Schaeffer. 

Bulbs can be furnished frosted, or of 
almost any desired color, either artificially 
dipped or in natural glass. 



19 








GENERAL ELECTRIC COMPANY 


50 Candle=power 50 Volt Lamp. 


A proper proportion should always 
be preserved between the size of bulb 
and the candle-power of an incandescent 
lamp. Too large a bulb is unnecessarily 
heavy, occupies much space and is bulky 
in appearance, while too small a bulb 
causes undue heating and blackening. 

The illustration of our standard 
50 candle-power low voltage lamp clearly 
shows the harmony of proportion in 
candle-power and size of bulb. The 
Edison lamp, as is well known by all 
users, also maintains a full ratio of 
light given to power consumed, to a 
greater degree than any other lamp. 
Our 50 candle-power lamps can be 
depended upon for accurate and perfect 
construction. 

DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size 
as in illustration. 

Filament—Loop. 

Voltages—45 to 90. 

Efficiency—3.1, 3.5 and 4 watts 
per candle. 

P'itted with Standard Edison 
Screw Base or any of the following 
bases: Westinghouse, Thomson-Hous- 
ton, United States, Brush-Swan, Hawk- 
eye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, 
or of almost any desired color, either 
artificially dipped or in natural glass. 



20 







general electric company 


100 and 150 Candle=power 50 Volt Lamps. 

The mechanical structure of the heavy filaments in high candle-power lamps requires 
special attention. We have found that the greatest strength and rigidity are secured by the 
use of the double loop as shown in the illustration on the following page. These loops are 
connected in multiple and burn as two separate carbons. The chances of failure are thus 
reduced one-half, for should one filament break the other remains 
and the lamp will burn at half candle-power. As great dependence is 
placed on every high candle-power lamp, reliability is of marked 
importance. The value of our careful and exact processes is strongly 
realized in this type of lamp. 

Special attention is called to the heavy currents carried by these 
high candle-power lamps and the consequent importance of having a 
large and certain area of eontact between base of lamp and socket. For these lamps 6 to 9 
amperes at 50 volts are required and on this account they should be ordered with bases to fit 
Keyless Socket for High Candle-power Lamps. (Cat. No. 8319). These sockets are specially 
designed to carry large currents, and smaller standard sockets in general use are not reliable for 
this purpose. These high candle-power lamps are preferably used in keyless sockets, but in 
any case the current should be turned off and on at the switch and not at the socket. 


EXCELLENCE 

OF 

CONSTRUCTION 


DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size as in illustration. 

Filament—Double loop—the two loops in multiple. 

Voltages—45 to 90. 

Efficiency, 100 candle-power lamp —3.1 and 3.5 watts per candle. 

Efficiency, 150 candle-power lamp—3.1 watts per candle. 

Based with High Candle-power Base to fit Socket, Cat. No. 8319 or with Standard Edison 
Screw Base or any of the following bases: Westinghouse, Thomson-Houston, United States, 
Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 




21 
























Standard 
100 Volt 
Incandescent 
Lamps 









GENERAL ELECTRIC COMPANY 


8 and 10 Candle=power 100 Volt Lamps. 

For service requiring lower candle-power lamps than the standard 16 candle-power, we 
offer our 8 and 10 candle-power lamps. The production of the commercial lamp of high efficiency 
and low candle-power is attended with even graver difficulties than are 
involved in the production of the standard 16 candle-power lamp. 
The extreme fineness of the filaments of 8 and 10 candle-power 
lamps renders them very sensitive to variations of voltage so that 
the life obtained will, in general, average below that obtained from the 
standard lamp. Wherever the type of lamp admits of a comparatively 
thick filament, stability is increased. Lamps of 50 volts and lamps of 
higher candle-power will thus always give better results 
than lamps that do not permit the use of a thick filament. 

As will be seen in the illustration, the filament is 
oval in form, anchored at the stem and possesses all the 
mechanical advantages enumerated in our description of 
the standard 16 candle-power lamp. The filament is secure 
against vibration, does not sag, and gives greater total 
illumination than any other type of filament. Although 
made in efficiencies of 3.1 watts per candle, the use of 
lamps of efficiencies higher than 8 candle-power 4 watts, 
or 10 candle-power 3.5 watts are not recommended, except 
in cases where the regulation is perfect. 

DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size as in illustration. 

Filament—Oval, Anchored. 

Voltages—90 to 125. 

Efficiency, 8 candle-power lamp — 3.1, 3.5 and 4 
watts per candle. 

Efficiency, 10 candle-power lamp—3.1, 3.5 and 4 
watts per candle. 

The 10 candle-power, 4 watt lamp has same size 
bulb as the standard 16 candle-power lamp. 

Pitted with Standard Edison Screw Base or any of 
the following bases: Westinghouse, Thomson-Houston, 

United States, Brush-Swan, Hawkeye, Mather, Perkins or 
Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 



COMPARATIVE 

AVERAGE 

LIFE 


25 













GENERAL ELECTRIC COMPANY 


16 Candle=power 100 Volt Lamp. 



THE STANDARD 
OF THE 
WORLD 


The 16 candle-power high voltage lamp is always the standard of comparison which 
distinguishes the perfected result of skill and experience applied in the finest equipped factory^ 
from that of less favored competitors. The difficulties met in making a perfect 50 volt lamp are 
multiplied when the 110 volt lamp is attempted. The increased voltage acting upon a finer 
filament results in rapid deterioration and loss of candle-power, unless its construction has been 
given careful attention by experienced workmen. The average manufacturer is, therefore, 
unable to produce a high voltage lamp of higher efficiency than 3.5 to 
5 watts per candle. The suc¬ 
cessful production by us of a 
commercial 3 watt, high volt¬ 
age lamp, has been largely 
instrumental in bringing in¬ 
candescent lighting to its 
present advanced stage. 

The Standard New Type Edison Lamp here 
illustrated is to-day the most extensively used lamp 
in the world and upon it has been concentrated the 
greatest amount of skill, time and attention. 

All its numerous good points cannot be shown 
in an illustration. Clean white light, uniform and 
highly sustained brilliancy, and good average life, are 
among the most notable superior qualities which can 
be appreciated only by using the lamp. The carbon 
filament is anchored securely in position, and thus 
prevented from vibrating or touching the glass. The 
filament is shaped to fit the bulb so as to form a 
bright sphere instead of two lines of light. The 
bulbs are uniform in size and shape, conducing not 
only to neat appearance, but to ease in installing and 
freedom from misfits in shades and holders. 

By our new process of chemically exhausting 
lamps, the thorough removal of gases in and about 
the filament and connections reduces the possibility 
of blackening and adds to the life and maintained 
brilliancy of the lamps. More important still, each 
lamp is separately exhausted, and uniformity of 
product is, therefore, absolutely assured. 


DESCRIPTION. 


Bulb—Moulded, Size as in illustration. Filament—Oval, Anchored. Voltages—90 to 125. 
Efficiency, 16, 20 and 24 candle-power lamps—3.1, 3.5 and 4 watts per candle. 

Fitted with Standard Edison Screw Base or any of the following bases: Westinghouse, 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished fiosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


26 










GENERAL ELECTRIC COMPANY 


32 Candle=power 100 Volt Lamp. 



The beauty of form and brilliancy of the oval filament are strikingly illustrated in our higher 
candle-power lamps. The oval filament produces a sphere of light exactly filling the bulb and its 
many advantages enumerated in the description of the 16 candle-power lamp are here accentuated. 
Our new chemical exhaustion process is of special advantage in the production of 32 candle-power 
lamps. It overcomes many of the special difficulties in the exhaustion of high candle-power lamps— 
blackening is reduced, maintenance of candle-power is increased and the quality of the average lamp 
is materially improved. 


DESCRIPTION. 

Bulb — Moulded, Pear-shaped, Size as in illustration. Filament — Oval, Anchored. 

Voltages — 90 to 125. Efficiency—3.1, 3.5 and 4 watts per candle. 

Fitted with Standard Edison Screw Base or any of the following bases: Westinghouse, 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


27 





GENERAL ELECTRIC COMPANY 


50 Candle-power 100 Volt Lamp. 


An anchor is of special value 
in retaining in form and position the 
heavy filament required in a 50 candle- 
power lamp. The compact shape of 
the oval avoids the necessity of using a 
large and bulky bulb. 

Our new exhaustion process pro¬ 
duces 50 candle-power lamps in which 
blackening is reduced, maintenance of 
candle-power increased and weak spots 
in filaments avoided. The construction 
of our 50 candle-power lamp is accurate 
and thorough — features that are 
especially desirable where reliance is 
placed on single lamps in service. 

DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size 
as in illustration. 

Filament—Oval, Anchored. 

Voltages—90 to 125. 

Efficiency—3.1, 3.5 and 4 watts 
per candle. 

Fitted with Standard Edison 
Screw Base or any of the following 
bases: Westinghouse, Thomson- 

Houston, United States, Brush-Swan, 
Flawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, 
or of almost any desired color, either 
artificially dipped or in natural glass. 



28 












GENERAL ELECTRIC COMPANY 


100 and 150 Candle=power 100 Volt Lamps. 

Reliability is a feature of prime importance in high candle-power lamps. When depend¬ 
ence is placed on a single lamp its failure from any cause is more serious than the failure of one 
of many lamps of lower candle-power. Our exact processes and individual treatment secure 
perfection in every lamp. The 100 and 150 candle-power lamp is shown in the illustration on the 
following page. For mechanical reasons we have found the double loop 
the most desirable form of filament for these lamps. The two loops 
being arranged in series, each loop is only half the length necessary with 
one continuous filament, and has many times the strength and rigidity. 
These lamps should be ordered with base to fit Keyless Socket for 
High Candle-power Lamps. (Cat. No. 8319). This socket is specially 
designed to carry large currents, and smaller standard sockets in general 
use are not reliable for this purpose. It is recommended that high candle-power lamps be used 
in keyless sockets, or in any case, that the current be turned off and on at the switch. 

DESCRIPTION. 

Bulb — Moulded, Pear-shaped, Size as in illustration. 

Filament — Double loop — the two loops in series. 

Voltages—90 to 125. 

Efficiency, 100 candle-power lamp- — 3.1 and 3.5 watts per candle. 

Efficiency, 150 candle-power lamp — 3.1 watts per candle. 

Based with High Candle-power Base to fit Socket, Cat. No. 8319, or with Standard Edison 
Screw Base or any of the following bases: Westinghouse, Thomson-Houston, United States, 
Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


DESIRABLE 
FORM OF 
FILAMENT 


29 




























GENERAL ELECTRIC COMPANY 


The Street Railway Lamp. 



It is essential in a street railway lamp that the filament be anchored. An unanchored 
filament, to withstand the shock and vibration of street car service, has to be so short and stiff 
that the light is limited to a very small area. The efficiency and maintained brilliancy of the 
lamp is thus reduced, as well as the general illumination of the car. The position of the anchor 
is also an important consideration. Anchoring the lower end of the filament to the inside of the 
bulb is objectionable, as it holds the filament too rigidly and the effect of a shock or jar is to 
break either the filament or the anchor. Excessive rigidity cannot be 
overcome by resting the fila¬ 
ment loosely in the anchor, 
since vibration of the filament 
against the anchor will cause 
it to wear away. With the 
anchor firmly connected to 
the stem or inside part of the lamp, as in the Edison 
oval filament, shown in the accompanying illustration, 
the ideal arrangement is secured. The filament is 
held so as to check vibration rather than to entirely 
prevent it. Freedom of vibration within proper 
limits is, therefore, allowed and the filament is not 
strained or weakened. With the anchor in the 
position shown, the whole filament vibrates together 
and there is practically no danger of the branches 
interlocking and short circuiting, as would be the 
case if one branch of the spiral were anchored rigidly 
to the side of the lamp, and the other branch free to 
vibrate and strike it. 

Another necessary consideration in the case of 
Railway Lamps is that they should have uniform 
current capacity since they are operated in series. 

Our Railway Lamps are made in three different 
classes, viz.: for 500 volt circuits, for 550 volt circuits 
and for 600 volt circuits. In each class, lamps are 
selected of a given amperage. In the 500 volt range, 
the current is .65 ampere. Thus carefully tested for 
candle-power and current these lamps are suited 
exactly to the requirements of street railway service 
and give uniform light and life. They have an 
efficiency of 4 watts per candle, at full 16 candle- 
power. Street Railway Lamps of 32 candle-power or other candle-powers are furnished to order. 


IDEAL 

ARRANGEMENT 
OF THE 
FILAMENT 


DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size as in illustration. Filament — Oval, Anchored. 
Efficiency—4 watts per candle. Furnished for operating five in series on circuits of a 
total of 500 volts, 550 volts or 600 volts. 

Fitted with Standard Pldison Screw Base or any of the following bases: Westinghouse, 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural, glass. 

31 













Special 

Incandescent 

Lamps 


GENERAL ELECTRIC COMPANY 


200 to 250 Volt Lamps. 


We furnished lamps for 200 and 250 volt circuits on special order for several years before 
the general public knew that such a lamp was practicable. 

Their successful use is now extended. 



A perfect vacuum is of the greatest importance with these high voltage lamps, for unless 
all the residual gases are thoroughly removed from the bulb the lamps are liable to explode at 
the high voltage. If an explosion, blowing the lamp into fragments 
VALUE OF OUR an d caus * n & serious short-circuits, does not occur in a badly exhausted 
lamp, the inside connec- 
EXHAUSTION tions may melt. Our new 

PROCESS process of exhaustion is, 

therefore, of special value 
in the production of these 
lamps. By this method, individual exhaustion in¬ 
sures a perfect vacuum in every lamp and reduces 
the danger of explosion or failure to a minimum. 

Owing to the increased strain to which the 
carbons or filaments are subjected by the high 
voltage, these lamps are uncommercial except in 
the lower efficiencies. The efficiency of our 
regular product is 4 watts per candle, and in its 
average life and maintenance of candle-power, 
corresponds to our standard 100 to 125 volt 3.1 
watt lamp. 

The illustration shows our latest type of 
200 to 250 volt lamp. The length of filament 
necessary in this type of lamp is most advantage¬ 
ously arranged in a double oval which is firmly 
held in position by two anchors. Such an 
arrangement is much neater than the method of 
anchoring to the inside of the bulb, and it avoids 
shadows. An anchor from the lower end of the 
filament to the inside of the bulb is useless, as the 
anchor breaks off with a slight shock and the 
weight of it destroys the filament. The Edison 
filament is so anchored as to allow some vibration 
and thus relieve the strain on the filament, but the 
vibrations are checked so as not to exceed proper 
limits. These lamps are made in 16 and 32 
candle-power. 


DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size as in illustration. Filament—Double oval, Double 
anchored. Voltages—200 to 250. Efficiency—4 watts per candle. 

Fitted with Standard Edison Screw Base or any of the following bases: Westinghouse 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


34 
















GENERAL ELECTRIC COMPANY 




Round Bulb Lamps. 

Lor window or other decorations and for all installations where a short bulb is desirable, 
we offer our Round Bulb Lamps. The bulbs are 2£" in diameter and make a very neat compact 
type of lamp. The oval form of anchored filament provides the best arrangement for the long 
filament of high voltage lamps in small round bulbs. In low voltage lamps the shorter and 
stiffer filament is well adapted to the spiral and loop forms. The round bulb lamps are 
frequently used in street railway service, in headlights and elsewhere. They can be obtained 
specially selected for amperes when desired for railway service. 



DESCRIPTION. 

Bulb—Moulded, Spherical, 2J" in diameter. 

Filament, 100 volts and over — Oval, Anchored. 

Filament, 50 to 00 volts—Spiral in 16 candle-power lamps, Loop in 8 and 10 candle-power 

lamps. 

Voltages — 45 to 125. 

Efficiency, 8 candle-power lamps — 3.1, 3.5, and 4 watts per candle. 

Efficiency, 10 candle-power lamps—3.1, 3.5, and 4 watts per candle. 

Efficiency, 16 candle-power lamps — 3.1, 3.5, and 4 watts per candle. 

Fitted with Standard Edison Screw Base or any of the following bases: Westinghouse, 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


35 









GENERAL ELECTRIC COMPANY 


Tubular Lamps. 



Tubular or “Bunghole ' Lamps are useful in confined or narrow places. They were origin¬ 
ally made for examining the interior of casks and barrels, the lamps being inserted through the 
bunghole. These /k lamps are also frequently used on candelabra and re¬ 
semble lighted candles. With the tubular form of bulb, the loop filament 

anchored at the s lower end to prevent sagging, is most suitable. 


DESCRIPTION. 


Bulb-Moulded, Size as in illustrations. Filament—Loop, Anchored. Voltages _ 45 to 125. 

Efficiency, 8 candle-power lamps—8.5 and 4 watts per candle. 

Efficiency, 10 candle-power lamps—3.1, 3.5 and 4 watts per candle. 

Efficiency, 16 candle-power lamps—3.1, 3.5 and 4 watts per candle. 

Fitted with Standard Edison Screw Base or any of the following bases: Westin^house 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. & 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. J 1 


36 






















GENERAL ELECTRIC COMPANY 


Stereopticon Lamps. 


DESCRIPTION. 



To meet a large and constantly increasing demand, we supply a specially designed lamp 
for stereopticons. A compact filament is here essential so that the light shall be radiated as 
nearly as possible from one 
point. As these lamps are 
required only in the higher 
candle-powers, the filament is 
necessarily heavy and must 
not be too closely bent. The 
convoluted spiral shown in 
the illustration meets these 


conditions most satisfactorily. 
The illustration shows 


the 100 and 150 candle-power 
stereopticon lamp. We make 
the 50 candle-power size in a 
smaller bulb 3£" in diameter. 
We also manufacture lower 


and higher candle-powers to 
special order. 


Bulb — Moulded, 

Round — For 100 to 150 
candle-power, Size as in illus¬ 
tration; for 50 candle-power, 

Size 3^" in diameter. Fila¬ 
ment — Convoluted spiral. 

Voltages — 45 to 125. 

Efficiency, 50, 100 and 
150 candle-power lamps — 4 
watts per candle. 

Fitted with Standard 
Edison Screw Base or any 
of the following bases: West- 
inghouse, Thomson-Houston, 

United States, Brush-Swan, 

Ilawkeye, Mather, Perkins or 
Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


37 





GENERAL ELECTRIC COMPANY 


The Edison Night Lamp. 

An objection to the Incandescent Light has always been that it could not be turned 
down or dimmed. This objection has been overcome in the Edison Night Lamp. A simple 
movement of the milled screw provided on this lamp changes the candle-power from sixteen to 
one. The device is economical as well as simple since the current consumed is reduced with the 
candle-power to a negligible amount. This lamp can be furnished without the screw, if a 
permanent low candle-power lamp is desired. The bulbs are always frosted. 

The Night Lamp is particularly adapted for use in hospitals, nurseries, bed-chambers, 
halls and closets. 


DESCRIPTION. 

Bulb—Moulded, Pear-shaped, Size as in illustration. 

Filament — Oval, Anchored. Voltages—45 to 125. 

Fitted with Standard Edison Screw Base or any of the following bases: YVestinghouse, 
Thomson-Houston, United States, Brush-Swan, Hawkeye, Mather, Perkins or Schaeffer. 

Bulbs in all cases furnished frosted. 



38 














GENERAL ELECTRIC COMPANY 


Resistance Lamp. 

Banks of lamps for resistance are in quite general use and are very satisfactory for 
moderate currents. We have for years had a large demand for specially made resistance lamps, 


of the type shown in the 
are furnished in tubular bulbs, 
closely and thus minimize space, 
nected in series to give required 
can be furnished of any desired 
and for currents up to five 
resistance and the current in 
is desired. 



illustration. Resistance lamps 
in order that they can be packed 
The filaments are loops con- 
resistance. Lamps of this type 
resistance up to 1000 ohms cold, 
amperes. In ordering state 
amperes at which this resistance 


DESCRIPTION. 

Bulb — Moulded, Tubular, Size as in illustration. 

Filament — Loop. Resistance — As stated above. 

Fitted with Standard Edison Screw Base or any of the following bases: Westinghouse, 
Thomson-Houston, United States, Brush-Swan, Hawkey e, Mather, Perkins or Schaeffer. 

Bulbs can be furnished frosted, or of almost any desired color, either artificially dipped or 
in natural glass. 


39 



















ORDERS FOR AND CORRESPONDENCE CON- 


CERNING MINIATUR E LAMPS AND APPLI¬ 
ANCES^ AND ANY SPE CIA L L AMPS NOT 
D ES CRIBED IN THIS CATALOGUE, SHOULD BE 
ADDRESSED TO 

E diso n Decorative and Miniature Lamp Dept.. 


General_Electric Company, 
Harrison, N. J. 












Miniature 

Lamps 

and 

Appliances 





GENERAL ELECTRIC COMPANY 


Candelabra and Decorative Lamps. 

The practical application of Candelabra Lamps in decorative interior lighting has become 
so general and so well understood that any special remarks in the sense of exploitation are 
unnecessary at this date. 

The Series Candelabra Lamps which were introduced by us a few years ago have 
constantly grown in public favor, and are now in extensive use, chiefly for decorative lighting in 
residences, hotels and other places to which they are eminently suitable. The favorable reception 
that this form of lighting has met, has led to a demand for lamps of the same general styles and 
sizes capable of being used in multiple, instead of in series, on circuits of from 100 to 120 volts. 

Anticipating such a demand, we produced several styles of multiple burning Candelabra 
Lamps, which are shown in the following pages. We have found them to be a product that has 
met with instant favor and, in consequence of their many points of excellence, the demand for 
them has rapidly grown. 

The Special Series Lamps have also retained their great popularity for all kinds 
of temporary and permanent decorative and electric sign work. In this branch we have 
also added a multiple burning lamp to meet a demand for such a type of lamp, to be used 
more especially in electric sign work. This lamp has filled many requirements for that 
special use that could not be met by the series lamps. All of these lamps, however, 
series and multiple, have their proper sphere of utility, according to the circumstances 
under which they are to be used. 

It is proper to call special attention also to our Sockets and Receptacles. Many 
improvements have been made in them, not only with regard to their usefulness and to 
the convenience of handling, but with a view to their appearance and increased 
safety from a fire underwriter’s standpoint. It will be found from a careful 
examination of the sockets and receptacles listed in the following pages, that we 
have so devised them as to provide for all contingencies that could be reasonably 
anticipated. 




Regarding Series Lamps. 


The lamps shown on pages 44, 46 and 47, are made especially for series 
burning on electric lighting circuits. 

Particular attention is called to the following general remarks on these lamps. 

If these remarks are carefully read before ordering or using any of these series lamps, 
purchasers will save themselves and us considerable trouble, expense and delay. 

The most important point in burning lamps in series is that the amperes of each of the 
lamps in any one series should be the same within three one-hundredths of an ampere. 

The voltage of the lamps may vary, but the sum of the voltages in any series must equal 
the voltage of the circuits within three volts. 

In selecting lamps for any one series, use only lamps of approximately the same amperes, 
and see that the sum of their voltages equals the voltage of the circuit. 

In replacing a lamp which has burned out in any series, use only a lamp of the same 
voltage and amperes as the one broken. 

In ordering series lamps to replace those burned out, give both voltage and amperes of 
those in use, also, voltage of circuit. 


43 







GENERAL ELECTRIC COMPANY 


Series Candelabra Lamps. 


Series candelabra lamps are made in five different styles, A, B, C, D and E, and are 
furnished, when specified, to be used two, three or four in series on electric lighting circuits of 
100 to 120 volts, and two in series or in multiple on circuits of 50 to 60 volts. 

Style A is always a 10 candle-power lamp. 

Styles B, C, D and E differ from each other only in the shape of the bulbs, but they all 
differ from the style A lamp in that the candle-power of each varies according to the number of 
lamps used in series. On 100 to 120 volt circuits, two lamps in series give 8 candle-power each— 
three in series, 5 candle-power each—four in series, 4 candle-power each. If burned in multiple 
on circuits of 50 to 60 volts, each lamp will give about 8 candle-power. 




STYLE A STYLE B STYLE C STYLE D STYLE E 

All colored candelabra lamps will be made of natural glass, except amber-colored, which 
will be dipped. 

Unless otherwise ordered the Style D lamp is frosted, as a better effect is thereby 
obtained. It is not made in colors. 


Amperes and volts are etched on each lamp. 

Note directions for ordering, page 46. 

The above lamps will fit Candelabra Sockets and Receptacles Nos. 1, 2, 3, 6 and 7, 
page 48. 


44 













GENERAL ELECTRIC COMPANY 


Multiple Candelabra and Sign Lamps. 



Multiple candelabra lamps, Styles A, B and D have been especially designed for burning 
in multiple on circuits of 100 to 120 volts. In ordering these lamps the voltage of the circuit 
should be specified and the lamps be designated as Multiple Candelabra Lamps, Styles A, B or D 
to distinguish them from the Series Candelabra Lamps of the same styles. 

The multiple sign lamp, Style F, was especially designed to fill a demand for small lamps 
to burn in multiple in illuminated signs having letters from ten inches to two feet in height. It 
has attained a great popularity for use in this connection, as well as in many other lines on 
account of its size, beauty, candle-power and economy in the use of current. It is an 8 candle- 


STYLE A STYLE B STYLE D STYLE F 

power lamp, is furnished for use in multiple on circuits of 100 to 120 volts, and takes a current 
of about .28 ampere. In ordering these lamps, the voltage of the circuit should be specified. 

All colored multiple candelabra and sign lamps will be made of natural glass, except 
amber-colored, which will be dipped. 

Unless otherwise ordered the Style D lamp is frosted, as a better effect is therety 
obtained. It is not made in colors. 

Note directions for ordering, page 43. 

The above lamps will fit Candelabra Sockets and Receptacles Nos. 1, 2, 3, 6 and 7, 
page 48. 


45 











GENERAL ELECTRIC COMPANY 


Special Series Lamps. 

The following lamps are called “Special Series” Lamps to distinguish them from 
Candelabra and Battery Lamps. We furnish these in four different candle-powers for burning 
in series on electric lighting circuits of 100 to 120 volts, or on circuits of 50 to 60 volts. 

The 8 candle-power lamp is used for decorative purposes where large units of light, but 
few in number, are desired. In illuminations covering a large area this lamp can be used 
advantageously. It is also used in multiple for illuminated signs on 50 to 60 volt circuits. 

Ihe 5 candle-power lamp is also used for decorative purposes where large units of light, 
but few in number, are desired, and it can be used advantageously in illuminations covering a 
large area. It is used quite extensively in decorative sign work where the effect to be obtained 
is not based upon the employment of large units of light but upon the special design or the 
number of lamps used. 



8 CANDLE-POWER. 

2 in Series on 100-120 Volts. 
In Multiple on 50- 60 Volts 
Current required for each 
series will average 
about .50 amp. 



5 CANDLE-POWER. 

4 in Series on 100-120 Volts. 
2 in Series on 50-60 Volts 
Current required for each 
series will average 
about .55 amp. 


3 CANDLE-POWER. 

8 in Series on 100-120 Volts. 

4 in Series on 50-60 Volts 
Current required for each 

series will average 
about 1 amp. 


I CANDLE-POWER. 

8 in series on 100-120 Volts. 
4 in Series on 50-60 Volts 
Current required for each 
series will average 
about .33 amp. 


The 3 candle-power lamp is used for decorative purposes in cases where plenty of current 
is obtainable. We do not recommend its use where lamps are to be placed close together, as in 
sign work and many cases of floral decorations, because it becomes quite hot in continual use. 

The 1 candle-power lamp is that which we most strongly recommend for sign and 
decorative work where lamps are to be placed close together. It gives a good light, generates 
very little heat, and each series requires only about one-third of an ampere of current. It is 
therefore, the best small lamp for series work, whether for interior signs, among flowers or 
otherwise. 


46 
















GENERAL ELECTRIC COMPANY 


Special Series Lamps.— continued. 

The theatrical lamp is made to give 1 candle-power, burning 16 in series on 100 to 120 
volt circuits or 8 in series on 50 to 60 volt circuits. Each series takes about one-half ampere of 
current. It is extensively used for theatrical purposes, for decorating dancers and 
producing special effects. This lamp is carried in stock as an unbased (or wire) 
lamp, and will be so shipped unless otherwise ordered. If desired it will be 
furnished fitted with miniature screw base to fit No. 4 Receptacle or No. 5 
Socket. 

All colored series lamps will be made of natural glass, except amber-colored, 
which will be dipped. 

Amperes and volts are etched on the 8 candle-power and 5 candle-power 

lamps. 

Note directions for ordering, page 43. 

The 8 candle-power and the 5 candle-power lamps will fit Candelabra Sockets 
and Receptacles Nos. 1, 2, 3, 6 and 7, page 48. 

The 3 candle-power and the 1 candle-power lamps will fit Miniature Lamp Socket and 
Receptacle Nos. 4 and 5, page 48. 



SPECIAL 

SERIES 

THEATRICAL 

LAMP 



47 





GENERAL ELECTRIC COMPANY 


Receptacles and Sockets. 

No. 1 is known as the Standard Round Candelabra Receptacle. It is made of non- 
combustible insulating material. This receptacle is especially designed for use on fixtures fitted 
with glass candles, the receptacle screwing into a central supporting tube, and the candles, when 
in place, completely covering both supporting tube and receptacle. It will receive lamps having 
candelabra screw base — pages 44 and 45, and the 8 and 5 candle-power lamps on page 46. 

No. 2 is the Standard Flat Base Candelabra Receptacle. It is made of porcelain and will 
receive lamps shown on pages 44 and 45, and the 8 and 5 candle-power lamps on page 46. 



NO. 1 RECEPTACLE. 


NO. 2 RECEPTACLE. 


NO. 3 SOCKET. 


NO. 4 RECEPTACLE. 


No. 3 is the Candelabra Socket. It is made of brass, with porcelain insulating parts and 
will leceive lamps shown on pages 44 and 45, and the 8 and 5 candle-power lamps on pa°'e 46 

No. 4 is the Standard Round Miniature Lamp Receptacle. It is made of porcelain and 
will receive the 3 and 1 candle-power lamps fitted with miniature screw base—pa°-es 46 and 47 
No. 5 is the Standard Socket for use with Miniature Lamps. It is made of brass with 
porcelain insulating parts, and will receive the 3 and 1 candle-power lamps fitted with miniature 
screw base—pages 46 and 47. 





NO. 5 SOCKET. NO. 6 RECEPTACLE. NO. 7 RECEPTACLE. 

No. 6 is a Special Receptacle made by us for sign work. It has been designed for 
strength and compactness and is very extensively used for sign work of all kinds. It is made of 
porcelain and will receive lamps shown on pages 44 and 45, and the 8 and 5 candle-power lamps 
on page 46. L ^ 

No. 7 is a Double-pole Fused Receptacle which has been designed to meet the require¬ 
ments of certain climatic conditions demanding the use of fuses in connection with the 
receptacle itself. It is also particularly suitable for many classes of inside work necessitating 
the use of an ornamental receptacle. This receptacle is made of porcelain and has a removable 
cap or cover concealing both connections and fuses, yet permitting ready access thereto It 
will receive lamps shown on pages 44 and 45, and the 8 and 5 candle-power lamps on page 46 


48 






GENERAL ELECTRIC COMPANY 


Shades for Miniature Lamps. 



The star shade here illustrated is made especially for certain classes of decorative work, 
and presents a very handsome and striking effect when the lamps are lighted. 


STAR SHADE WITH COLORED EDGING. 

The shades for miniature lamps illustrated below are furnished in the following colors: 
Red, White, Blue and Green, with edgings of different colors. 



SHADES FOR MINIATURE LAMPS. 



SHADE-HOLDER ATTACHMENT. 

The type of Shade-holder Attachment shown in the illustration is furnished for use with 
Sockets Nos. 3 and 5. It is made of brass and may be readily attached. As these attachments 
are not interchangeable for Sockets Nos. 3 and 5, customers should be careful in ordering to 
state with which socket the attachment is intended to be used. 


49 




GENERAL ELECTRIC COMPANY 


Battery Lamps. 



The lamps shown on the following pages are made especially for use with batteries and 
are not adapted for series work. They should not under any circumstances be used for series 
lighting. 


BATTERY LAMP. 

FOR STANDARD SOCKET. 

Battery lamps as shown in the above illustration are extensively used for railway-carriage 
lighting and for other purposes in connection with storage battery plants. They are made up 
in standard bulbs of about the size shown in the cut, and can be furnished to fit all standard 
sockets. 

They are made of 8, 10, 16, 20 and 24 candle-power, and from 8 to 45 volts. 

These lamps are furnished at an economy of from 2.5 to 4 watts per candle. 


50 








GENERAL ELECTRIC COMPANY 


Battery Lamps.— continued. 

The battery lamps here illustrated are described in the accompanying table. YVe make 
NO LAMPS TAKING LESS THAN 3 VOLTS. 





DESCRIPTION. 

CANDLE-POWER. 

ELECTRO¬ 
MOTIVE FORCE. 

VOLTS. 

CURRENT REQUIRED, 

APPROX. AMPERES. 



Standard Battery Lamp . . . 

\ Candle 

3 to 5 

.80 to 1.35 



Standard Battery Lamp . . . 

1 Candle 

4 to 6 

.90 to 1.40 



Standard Battery Lamp . . . 

2 Candles 

4 to 7 

1.00 to 1.50 



Standard Battery Lamp . . . 

3 Candles 

5 to 7 

1.25 to 2.00 



Standard Battery Lamp . . . 

4 Candles 

7 to 9 

1.25 to 2.00 



Standard Battery Lamp . . . 

6 Candles 

9 to 12 

1.50 to 2.25 



Dental Lamp, Side Seal . . . 

% Candle 

3 to 5 

.80 to 1.35 



Special Dental, Side Seal . . . 

\ Candle 

3 to 5 

.80 to 1.35 



Special Dental, Bottom Seal . . 

^ Candle 

3 to 5 

.80 to 1.35 



Surgical Lamp. 

£ Candle 

3 to 5 

.80 to 1.35 



Pea Lamp. 

\ Candle 

3 to 5 

.80 to 1.35 



51 





































GENERAL ELECTRIC COMPANY 


Battery Lamps. —continued. 


The telephone lamps here shown are specially made for use on telephone switchboards. 
They are designed to take a very small quantity of current. The volts and current required are 
as follows: 

One-fourth candle-power, 10 volts, .14 ampere. 

One-half candle-power, 20 volts, .14 ampere. 

These lamps are always furnished with miniature screw base to fit No. 4 Receptacle or 
No. 5 Socket, unless otherwise ordered. 




The bicycle lamp here shown is the form and type of lamp most generally used with 
storage or primary battery for bicycle headlights, etc. It is of high economy, giving about f of 
a candle-power at 4 volts and .50 ampere. This lamp is always furnished with miniature screw 
base to fit our No. 4 Receptacle or No. 5 Socket, unless otherwise ordered. 

The miners lamp is a flat lamp of one candle-power, arranged with loops at the top and 
bottom, in order that it can be hooked upon springs in the miner’s lantern and so held steady. 
This lamp requires about 3.5 to 5.5 volts, and .90 to 1.40 amperes. 



4 CANDLE 
FLAT LAMP. 



iCANDLE 
FLAT LAMP. 



4 CANDLE 
SPHERICAL LAMP. 


The electromotive force required for the flat lamps is 3 to 5 volts, and 7 to 9.5 volts. The 
current required is .80 to 1.35, and 1.25 to 2 amperes. 

The electromotive force required for the spherical lamp is 7 to 9.5 volts. The current 
required is 1.25 to 2 amperes. 


52 









GENERAL ELECTRIC COMPANY 


Battery Lamps.— continued. 


The kinetoscope lamp is that originally adopted for use in the Edison Kinetoscope, and 
it is still used therewith all over the world. As will be seen from the illustration, the filament 
is in spiral form, thus providing for concentration of the light in one spot. This lamp is always 
furnished with miniature screw base, to fit No. 4 Receptacle or No. 5 Socket, unless otherwise 
ordered. 


The microscope lamps are for one-half candle-power. The electromotive force required is 
3 to 5 volts and the current required is .80 to 1.B5 amperes. 



KINETOSCOPE LAMP 
4 C.P. 8 VOLTS. 



MICROSCOPE LAMP MICROSCOPE LAMP MICROSCOPE LAMP 20 CANDLE 

LAROE. SIDE SEAL. SMALL. SPIRAL LAMP. 


The carbon of the 20 candle-power spiral lamp is made in spiral form, as shown in the 
illustration, and the lamp is therefore adapted for special purposes where a brilliant and 
concentrated light is desired. This lamp is furnished without base unless otherwise ordered. 

Electromotive force required is from BO to 38 volts, and current of from 1.75 to 2.50 
amperes. 


STICK-PIN LAMP. 



WATCH-CHARM LAMP. 


We have not heretofore listed the stick-pin and watch-charm lamps, having usually 
supplied them only on special order. The demand for these ornaments has of late become so 
general that we have decided to carry them in stock regularly. The lamps are similar in 
appearance to an ordinary incandescent lamp, but they are only dummies and cannot be 
lighted. 


53 











ORDERS FOR AND CORRESPONDENCE CON- 


CERNING MINIATURE LAMPS AND APPLI¬ 
ANCES, AND :ANY SPECIAL LAMPS NOT 
DESCRIBED I N THIS C ATAL OGUE, SHOULD B E 
ADDRESSED TO 

Edison Decorative and Miniature Lamp Dept., 
General Electric Company, 


Harrison, N. J. 










Appendix 

of 

Information 

on 

Incandescent 

Lamps 



































' ' ' 
































GENERAL ELECTRIC COMPANY 


Life and Candle=power of Lamps. 


Since the prime function of an incandescent lamp is to give light, the best lamp is 
that which gives maximum light at minimum cost. This is an exceedingly simple axiom 
and yet few users of lamps follow it out in practice. Lamps are repeatedly selected for long 
life irrespective of good, uniform candle-power. Lamps are often continued in use long after 
their candle-power has seriously diminished. 


An examination of the characteristics of an incandescent lamp will give a clear 
understanding of the principles applying to their selection and use. A theoretically perfect 
lamp would maintain its normal candle-power indefinitely, or until the lamp was broken. In 
practice the deterioration of the lamp filament causes a steadv-loss of candle-power. 

The drop in candle-power is a characteristic of an incandescent lamp always to be borne 
in mind. The relative drop or loss of candle-power, other things being equal, determines the 
comparative value of different lamps. We may have a lamp that loses 
50% in candle-power inside of 200 hours on a 3.1 watt efficiency basis. 
This type is almost invariably furnished by the inexperienced manufac¬ 
turer, and there are many such lamps in the market. Considered 
from the standpoint of life only, such lamps are excellent, because their 
filaments deteriorate to such a degree that it is practically impossible 
to supply enough current to brighten them up to the breaking point, 
but no discerning station manager would want such dim lamps even with unlimited life. 
As in the selection of incandescent lamps so in their use—the exclusive consideration of life 
leads to poor results. Loss of candle-power in a lamp sooner or later makes it uneconomical to 
continue in use. 


REGARDING 
LOSS IN 

CANDLE=POWER 


There is no lamp yet made which is economical to burn over IOOO hours , and in the great 
majority of cases the limit is under 6oo hours. 

An incandescent lamp is nothing more than a transformer, receiving current and 
transforming it into light. After a certain time this transformer may lose 50% in efficiency, 
taking practically the same current, but giving only about one-half the light. A boiler or an 
engine suffering such loss in efficiency would be promptly repaired or replaced. The renewal of 
incandescent lamps is even more important. The old lamps jeopardize the customer’s trade with 
their poor and expensive light. A customer cares little how efficiently a station is operated, but 
is much concerned about the quality of light furnished. At the present price of lamps, doubling 
the number of lamp renewals adds little to cost of operation, while it increases the lighting 
efficiency 40% to 50%. Some stations attempt to correct the dimness of old lamps by raising 
the voltage, but this is bad practice, for the increased pressure damages every new lamp placed 
in circuit. These principles are carefully observed by many of the large lighting companies, and 
a force of men is employed to weed out and replace all dim lamps. Some such means of 
keeping the average life below 600 hours should be adopted by every lighting company that has 
any regard for the economical production of light or the satisfaction of their customers. 

A simple method is to fix the average life at 600 hours or less and then determine from 
the station record how many lamps should be renewed each month to keep the average life 
within this limit. The required number of lamps should be renewed each month. 

If, for example, a station decides on an average life not to exceed 600 hours and the 
station records show that on the average 60,000 lamp hours of current are supplied monthly, 

, . ... 60,000 inn , 
then it would be necessary to renew - — or 100 lamps a month. 




GENERAL ELECTRIC COMPANY 


The Importance of Good Regulation. 

PROPER SELECTION AND USE OF TRANSFORMERS. 

Poor regulation of voltage probably results in more trouble with customers than any 
other fault in electric lighting service. 

Some Central Station managers act on the theory that so long as the life of the lamp is 
satisfactory, an increase of voltage, either temporary or permanent, will increase the average 
light. The fact is that when lamps are burned above their normal rating the average candle- 
power of all the lamps on the circuit is decreased, and if the station is on a meter basis, it 
increases the amount of the customers’ bills. 

Excessive voltage is thus a double error — it decreases the total light 
of the lamps, and increases the power consumed. The loss of light 
displeases the customers and discredits the service. If light is sold by 
meter, the increased power consumption dissatisfies the customers; if 
light is sold by contract, the additional power is a dead loss to the 
station. If increased light is needed, 20 candle-power lamps should be 
installed instead of raising the pressure. Their first cost is the same as 
16 candle-power lamps; they take but little more current than 16 candle-power lamps operated 
at high voltage and give greater average light. 

Increased pressure also decreases the commercial life of the lamp, and this decrease is at 
a far more rapid rate than the increase of pressure as shown in the following table. This table 
shows the decrease in life of standard 3.1 watt lamps due to increase of normal voltage. 


Per Cent, of Normal Voltage. 

Life Factor. 

100 

1.000 

101 

.818 

102 

.681 

103 

.662 

104 

.452 

105 

.374 

106 

.310 


From this table it is seen that 3% increase of voltage halves the life of a lamp, while 6% 
increase reduces the life by two-thirds. 

Irregular pressure, therefore, necessarily results in the use of lamps in which the power 
consumption per candle is greater than a well regulated pressure would allow. The result is 
reduced capacity of station, and reduced station efficiency. 

These remarks apply with special force to alternating current stations, 
since we have here two sources of possible irregularity in voltage—the 
generator and the transformer. Poor regulation is most apt to occur in 
the transformers and the utmost care should, therefore, be taken in 
their selection and use. The efficiency of the average lamp on alter¬ 
nating systems is nearly 4 watts per candle. With good regulation 
obtained by the intelligent use of modern transformers, the use of 
lamps of an efficiency of 3.1 watts per candle becomes practicable. It is thus possible to 
save 25% in power consumption at the lamps and increase the capacity of the station and 
transformers by the same amount. 

In the past two years there has been a marked advance in the method of making trans¬ 
former installations. The general adoption of higher voltage secondaries gives smaller loss in 


THE SAVING 
RESULTING 
FROM GOOD 
REGULATION 


EVILS OF 

EXCESSIVE 

VOLTAGE 


58 




GENERAL ELECTRIC COMPANY 


MODERN 

TRANSFORMER 

PRACTICE 


wires and permits the use of larger transformer units, thus greatly improving the regulation. 
On this account 50 volt lamps are gradually going out of use. The replacement of a number of 
small transformers by one large unit, and of old, inefficient transformers 
by modern types, has also been of immense advantage to stations. 
A large number of stations, however, still retain these old transformers, 
and load their circuits with large numbers of small units. Such 
stations necessarily suffer from loss of power, bad regulation and a 
generally deteriorated lighting service. Simply as a return on the 
investment, it would pay all such stations to scrap their old transformers 
and replace them with large and modern units. 

Proper care in the selection of transformers considers the quality and the size. Quality 
is the essential consideration and should have preference to first cost. No make of transformer 
should be permitted on a station’s circuit that does not maintain its voltage well within 3% from 
full load to no load. The simple rule regarding size is to use as large units as possible and thus 
reduce the number of units as far as the distribution of service permits. Every alternating 
station should aim to so improve regulation as to permit the satisfactory use of 3 watt lamps. 

Good regulation is eminently important to preserve the-average life and light of the lamps, 
to prevent the increase of power consumed by the lamps, and to permit the use of lamps of lower 
power consumption, so that both the efficiency and capacity of the station may be increased. 

Constant voltage at the lamps can be maintained only by constant use of reliable, portable 
instruments. No switchboard instrument should be relied on, without frequent checking by 
some reliable standard. Owing to the varying drop at different loads, 
HOW TO constant voltage at the station is not what is wanted. Pressure readings 

MAINTAIN should be taken at customers’ lamps at numerous points, the readings 

being made at times of maximum, average and minimum load. Not 
CONSTANT less than five to ten readings should be made at each point visited, the 

PRESSURE volt-meter being left in circuit for four or five minutes and readings 

taken every fifteen seconds. The average of all the readings gives 
the average voltage of the circuits. Lamps should be ordered for this voltage, or if desired, 
the voltage of the circuits can be reduced or increased to suit the lamps in use. The practical 
points are to determine the average voltage at frequent periods with a portable volt-meter 
at various points of the circuits, and then to arrange the voltage of the lamps and circuits so 
that they agree. 


Candle=hours-The Measure of Lamp Value. 

The amount of light given by lamps of the same efficiency is the only proper measure of 
their value. The amount of light given, expressed in candle-hours, is the product of the 
average candle-power for a given period by the length of the period in hours. 

Many of the best Central Station managers consider that a lamp has passed its useful life 
when it has lost 20% of its initial candle-power. In the case of a 16 candle-power lamp the 
limit would be 12.8 candle-power. The period of time a lamp burns until it loses 20% of its 
candle-power may therefore be accepted as its useful life. The product of this period in hours 
by the average candle-power gives the “candle-hours” of light for any given lamp. 

The better a lamp maintains its candle-power under equal conditions of comparison the 
greater will be the period of “useful life” and therefore, the greater will be the “candle-hours.” 
This measure is, therefore, the only proper one with which to compare lamps and determine 
their quality. 

59 




GENERAL ELECTRIC COMPANY 


The practical method of comparison is as follows:—Lamps of similar candle-power and 
voltage are burned at the same initial efficiency of 3.1 watts per candle on circuits whose 
voltage is maintained exactly normal. At periods of 50, 75 or 100 hours the lamps are removed 
from the circuits and candle-power readings taken, the lamps being replaced in circuit at the end 
of each reading. Readings are thus continued until the candle-power drops to 80% of normal. 
The results obtained are then plotted in curves, and the areas under these curves give the 
“candle-hours” and the relative value of the different lamps. 

Variation in Candle=power and Efficiency. 

In the following table is shown the variation in candle-power and efficiency of standard 
3.1 watt lamps, due to variation of normal voltage. 


Per Cent, of 

Per Cent, of 

Efficiency in 

Normal Voltage. 

Normal Candle-power. 

Watts Per Candle. 

90 

53 

4.68 

91 

57 

4.46 

92 

61 

4.26 

93 

65 

4.1 

94 

69i 

3.92 

95 

74 

3.76 

96 

79 

3.6 

97 

84 

3.45 

98 

89 

3.34 

99 

94| 

3 22 

100 

100 

3.1 

101 

106 

2.99 

102 

112 

2.9 

103 

118 

2.8 

104 

124! 

2.7 

105 

131! 

’ 2.62 

106 

138! 

2.54 


Example.—Lamps of 16 candle-power, 105 volts, and 3.1 watts, if burned at 98% of 
normal voltage, or 103 volts, will give 89% of 16 candle-power, or 14^ candle-power and the 
efficiency will be 3.34 watts per candle. 

Lamp Renewals. 

The importance and necessity of proper lamp renewals applies forcibly to all stations, 
regardless of the cost of power and whether lamp renewals are charged for or furnished free. 
The policy of free lamp renewals at the present low price of lamps is, however, preferable for 
both station and customer. Free lamp renewals give a station that full and complete control of 
their lighting service so requisite to perfect results. 

Since, however, a large number of companies charge for renewals, we offer some suggestions 
as to the best method of inducing customers to renew their old lamps, for it is evident that some 
inducement is necessary. 

Offering new lamps in exchange for dim lamps at a reduction in price is one good method. 
A customer, for example, would save by paying say half price for the renewal of a dim lamp, 
instead of waiting and paying full price when the lamp burns out. 


60 




GENERAL ELECTRIC COMPANY 


Another method is to offer lamps for renewals at less than cost, say 15 cents each, and 
reserve the right to say when lamps shall be renewed. Such a plan works well, as no customer 
can justly complain when the company renews lamps at less than cost. 

As profit on the sale of lamps is certainly secondary in importance to the sale of current 
and the improvement in quality of light, either of the above plans should commend themselves 
to all Central Stations not furnishing free renewals. 

Whatever method be adopted, the one chief principle of good economical lighting service 
should never be forgotten, viz.: that the average life of lamps should never exceed 600 hours. 

Points to be Remembered. 

That a constant pressure at the lamps must be maintained. ' 

That the lamps are not to be used to the point of breakage — they should be renewed when 
they become dim. 

That satisfaction to customers, and the success of electric lighting is dependent upon good, 
full and clear light, which old, black and dim lamps cannot give. 

That to furnish a good, full and clear light is as much a part of the Lighting Company’s 
business as to supply current to light the lamps. 

That a company should always endeavor to keep the average life of lamps within 
600 hours. 

That to renew dim lamps properly on the free renewal system, inspectors should examine 
the circuits regularly when the lamps are burning. If lamp renewals are charged to customers, 
induce them to exchange their dim lamps. 

Faults in Incandescent Lamps. 

RAPID LOSS OF CANDLE=POWER. 

Rapid loss of candle-power is one defect in incandescent lamps, and we have shown that 
all lamps suffer a gradual loss of candle-power as they are used. A very rapid loss in candle- 
power is, however, a real fault, due to inexperienced manufacture, or use at excessive voltage. 
The remedy is to purchase only lamps of standard reputation produced by the experienced 
manufacturer and to maintain the pressure at normal on the lamps. The pressure should be 
carefully tested with accurate portable instruments at the lamp sockets, and if found high, the 
pressure should be regulated to accord with the voltage of lamps, or lamps supplied to accord 
with the pressure. 

BLACKENING OF BULBS. 

Another defect in incandescent lamps is the blackening of bulbs, although this is more 
often a supposed defect than a real one. A lamp may lose in candle-power and show but little 
blackening, and on the other hand, a lamp may get quite black and lose little in candle-power. 
Thus a 50 volt lamp which has a more stable filament than the 110 volt lamp often shows 
considerable blackening with little loss of candle-power. 

Blackening in good lamps results from either high pressure or excessive life. This is 
a supposed fault. The best of lamps, if burned too long, will always show a certain amount of 
blackening. The remedies are, of course, regulation of pressure and frequent renewals. 

The above are the most important defects to be found in incandescent lamps. 


61 



GENERAL ELECTRIC COMPANY 


General Illumination. 

The subject of illumination has been divided by Mr. E. L. Elliott, to whom we are 
indebted for many suggestions, into the following sub-divisions: Intensity or Brilliancy, 
Distribution, Diffusion and Quality. 

INTENSITY OR BRILLIANCY. 

1 he average brilliancy of illumination required will depend on the use to which the light 
is put. “A dim light that would be very satisfactory for a church would be wholly inadequate 
for a library and equally unsuitable for a ballroom.” 

The illumination given by one candle at a distance of one foot is called the “candle-foot ” 
and is taken as a unit of intensity. In general, intensity of illumination should nowhere be less 
than one candle-foot, and the demand for light at the present time quite frequently raises the 
brilliancy to double this amount. As the intensity of light varies inversely with the square of 
the distance, a 16 candle-power lamp gives a candle-foot of light at a distance of four feet. A 
candle-foot of light is a good intensity for reading purposes. 

Assuming the 16 candle-power lamp as the standard, it is generally found that two 
16 candle-power lamps per 100 square feet of floor space give good illumination, three very 
bright, and four brilliant. 1 hese general figures will be modified by the height of ceiling, color 
of walls and ceiling and other local conditions. The lighting effect is reduced, of course, by an 
increased height of ceiling. A room with dark walls requires nearly three times as many lights 
for the same illumination as a room with walls painted white. With the amount of intense light 
available in arc and incandescent lighting, there is danger of exceeding “ the limits of effective 
illumination and producing a glaring intensity,” which should be avoided as carefully as too 
little intensity of illumination. 

DISTRIBUTION OF LIGHT. 

Distribution considers the arrangement of the various sources of light and the 
determination of their candle-power. The object should be to “secure a uniform brilliancy on a 
ceitain plane, or within a given space. A room uniformly lighted, even though comparatively 
dim, gh es an effect of much better illumination than where there is great brilliancy at some 
points and comparative darkness at others. The darker parts, even though actually light 
enough, appear dark by contrast, while the lighter parts are dazzling. For this reason naked 
lights of any kind are to be avoided, since they must appear as dazzling points, in contrast wfith 
the general illumination.” 

The arrangement of the lamps is dependent very largely upon existing conditions. In 
factories and shops, lamps should be placed over each machine or bench so as to give the 
necessary light for each workman. In the lighting of halls, public buildings and large* 3 rooms, 
excellent effects are obtained by dividing the ceilings into squares and placing a lamp in the 
center of each square. The size of square depends on the height of ceiling and the intensity of 
illumination desired. Another excellent method consists in placing the lamps in a border along 
the walls near the ceiling. 

Lor the illumination of show windows and display effects, care must be taken to 
illuminate by reflected light. The lamps should be so placed as to throw their rays upon the 
display without casting any direct rays on the observer. 

The relative value of high candle-power lamps in case of an equivalent number of 16 candle- 
power lamps is worthy of notice. Large lamps can be efficiently used for lighting large 


62 




GENERAL ELECTRIC COMPANY 


areas, but in general, a given area will be much less effectively lighted by high candle-power 
lamps than by an equivalent number of 16 candle-power lamps. For example, sixteen 64 candle- 
power lamps distributed over a large area will not give as good general illumination as sixty-four 
16 candle-power lamps distributed over the same area. High candle-power lamps are chiefly 
useful when a brilliant light is needed at one point, or where space is limited and an increase in 
illuminating effect is desired. 


DIFFUSION OF LIGHT. 

“ Diffusion refers to the number of rays that cross each point. The amount 
of diffusion is shown by the character of the shadow. Daylight on a cloudy day may be 
considered perfectly diffused; it produces no shadows whatever. The light from the electric 
arc is least diffused, since it emanates from a very small surface; the shadows cast by it have 
almost perfectly sharp outlines. It is largely due to its high state of diffusion that daylight, 
though vastly more intense than any artificial illumination, is the easiest of all lights on the 
eyes. It is a common and serious mistake, in case of weak or overstrained eyes to reduce the 
intensity of the light, instead of increasing the diffusion.” 

QUALITY OF LIGHT. 

“Aside from difference in intensity, light produces many different effects upon 
the optic nerves and their centers in the brain. These different impressions we ascribe to 
difference in the quality of the light. Thus, ‘hard light,’ ‘cold light,’ ‘mellow light,’ 
‘ambient light,’ etc., designate various qualities. Quality in light is exactly analogous to 
timbre or quality in sound, which is likewise independent of intensity. The most obvious 
differences in quality are plainly those called color. But color is by no means the element of 
quality. The proportion of invisible rays and the state of diffusion, are highly important factors, 
but on account of not being directly visible, they have been generally overlooked, and are but 
imperfectly understood.” 



63 





GENERAL ELECTRIC COMPANY 


Luminosity of Incandescent Lamps. 

As showing the quality of the incandescent light, we present here a curve showing the 
relative luminosity of an incandescent lamp at different regions of the visible spectrum. 

On this subject Mr. E. L. Nichols states the following: 

“The most important wave lengths, so far as light-giving power is concerned, are those 
which form the yellow of the spectrum and the relative luminosity falls off rapidly both toward 
the red and the violet. The longer waves have, however, much more influence upon the candle- 
power than the more refrangible rays. 



“ Luminosity is the factor which we must take into account in seeking a complete 
expression for the efficiency of any source of illumination, and the method to be pursued in the 
determination of luminosity must depend upon the use to which the light is applied. If we 
estimate light by its power of bringing out the colors of natural objects, the value which we 
place upon the blue and violet rays must be very different from that which would be ascribed to 
them, if we consider merely their power of illumination as applied to black and white. In a 
picture gallery, for instance, or upon the stage, the value of an illuminant increases with the 
temperatui e of the incandescent material out of all proportion to the candle-power, whereas, 
candle-power affords an excellent measure of the light to be used in a reading room.” 

Relative Value of Arc and Incandescent Lighting. 

The relative value of the arc and incandescent systems of lighting is frequently difficult to 
determine. Incandescent lamps have the advantage that they can be distributed so as to avoid the 
shadows necessarily cast by one single source of light. Arc lamps used indoors with ground or 
opal globes cutting off half the light, have an efficiency not greater than two or three times that 

64 
















GENERAL ELECTRIC COMPANY 


of an incandescent lamp. Nine 50 watt, 16 candle-power lamps consume the same power as one 
full 450 watt arc lamp. It has been found that unless an area is so large as to require 200 to 300 
incandescent lights distributed over it, arc lamps requiring equal total power will not light the 
area with as uniform brilliancy. 

The Correct Use of Light. 

HOW TO AVOID HARMFUL EFFECTS ON THE EYES. 

An objection frequently urged against the incandescent lamp is that it is harmful to the 
eyes and ruins the sight. This is true only in so far as the lamp may be improperly used. 
Any form of light as frequently misused would produce the same harmful results. Few people 
think of attempting to read by an unshaded oil lamp, and yet many will sit in the glare of a 
clear glass incandescent lamp. Incandescent lamps are more generally complained of because, 
unlike oil or gas, they can be used in any position. Bookkeepers and clerks are often seen with 
an incandescent lamp at the end of a drop hanging directly in front of their eyes—an impossible 
position of the light from gas or oil. 

The first hygienic consideration in artificial lighting is to avoid the use of a single bright 
light in a poorly illuminated room. In working under such a light, the eye is adapted to the 
surrounding darkness and yet there is one spot in the middle of the eye that is kept constantly 
fixed on the very bright light. The brilliancy of the single light acting on the eye adjusted to 
darkness works harm. There should be a general illumination of the room in addition to any 
necessary local light. If sufficient general illumination is provided, the eye is adjusted to the 
light, and the local light can be safely used. The ideal arrangement provides general illumination 
so strong that a pencil placed on the page of a book casts two shadows of nearly equal 
intensity—one coming from the general light and the other from the local light. 

Care should also be taken to prevent direct rays from striking the eye. The light that 
reaches the eye by day is always reflected. In reading or writing, to avoid shadows, the light 
should come over the left shoulder. Only the reflected rays can then reach the eye. 

Another point to be avoided is the careless general use of clear glass, unshaded lamps. 
Frosted bulbs should be used in place of clear glass where soft light for reading is required. The 
intensity of light reflected from a small source is increased, and intense light injures the eye. 
With a clear glass globe the whole volume of light proceeds directly from the small surface of 
the lamp filament. With a frosted bulb the light is radiated from the whole surface of the bulb 
and while the total illuminating effect is practically undiminished, the light is softened by 
diffusion to the great comfort and relief of the eyes. 

Finally, the use of old, dim and blackened lamps giving but a small fraction of their proper 
light is very often a source of trouble in not supplying a sufficient quantity of light. Users of 
lamps are not often aware of the loss in candle-power a lamp undergoes and so it happens that 
lamps are retained in use long after their efficient light giving power has vanished. Proper 
attention to lamp renewals on the part of Central Stations is necessary to correct this evil. 

The correct use of light requires: 

That there should be general illumination in addition to the light near at hand. 

That only reflected light should reach the eye. The light should be so placed as to throw 
the direct rays on the book or work and not in the eye. 

That the light should be placed so that shadows will not fall on the work in hand. 

That shades and frosted bulbs should be used to soften the light. 

That lamps be frequently renewed to keep the light up to full candle-power. 


<v 


\ 


65 




INDEX 


THE MANUFACTURE OF LAMPS . 9 

THE SELECTION OF LAMPS . . 12 

THE PROPER USE OF LAMPS . . 14 

STANDARD 50 VOLT LAMPS : 

8 and 10 Candle-power . . .17 

16 Candle-power.18 

32 Candle-power.19 

50 Candle-power.20 

100 and 150 Candle-power . . .21 

STANDARD 100 VOLT LAMPS: 

8 and xo Candle-power . . .25 

16 Candle-power.26 

32 Candle-power.27 

50 Candle-power.28 

100 and 150 Candle-power . . .29 

Street Railway Lamp . . .31 

SPECIAL INCANDESCENT LAMPS: 

200 to 250 Volt Lamps . . -34 

Round Bulb Lamps . . . -35 

Tubular Lamps.36 

Stereopticon Lamps . . . .37 

Edison Night Lamp . . . .38 

Resistance Lamp. 39 


MINIATURE LAMPS AND APPLIANCES: 

Candelabra and Decorative Lamps . 43 

Regarding Series Lamps . . -43 

Series Candelabra Lamps . . *44 

Multiple Candelabra and Sign Lamps . 45 

Special Series Lamps . . . .46 

Receptacles and Sockets . . .48 

Shades for Miniature Lamps . . 49 

Battery Lamps. 5 ° 

Stick-pin and Watch-charm Lamps . 53 

APPENDIX: 

Life and Candle-power of Lamps . 57 

The Importance of Good Regulation . 58 

Candle Hours—The Measure of Lamp 

Value.59 

Variation in Candle-power and Efficiency 60 

Lamp Renewals.60 

Points to be Remembered . . .61 

Faults in Incandescent Lamps . .61 

General Illumination . . . .62 

Luminosity of Incandescent Lamps . 64 

Relative Value of Arc and Incandescent 

Lighting . . . . .64 

The Correct Use of Light . . -65 



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